CCNA Static Routes: Manual Summarization

Bundle lab

Hands-on CCNA static routing and manual summarization lab using a compact HQ–Branch–Remote topology. You will replace three specific static routes to Branch networks with a single /22 summary at HQ, verify end-to-end host reachability, observe the routing table reduction, and prevent over-aggregation loops by adding a Null0 discard route at Branch. A recommended step has you add the same /22 summary at Remote (replacing its default) to practice summarization on both sides.

Learning objectives

• Calculate a correct /22 manual summary for three contiguous /24 networks.
• Replace multiple specific static routes with a single summarizing static route at HQ.
• Verify summarized routing provides reachability for all component subnets from end hosts.
• Observe routing table reduction at HQ after summarization.
• Troubleshoot over-aggregation side effects and prevent loops with a targeted Null0 discard at Branch.
• Deploy the same summary at Remote by replacing its default route.

Troubleshooting focus

• CLIENT-REMOTE cannot ping CLIENT-BR at 10.20.1.10: run show ip interface brief on each router first and correct any down or misaddressed interface. Both ends of a /30 transit must carry matching masks.
• A static route is installed but traffic does not follow it: confirm its next hop is the neighbor's address on the directly connected link — 10.0.12.2 from RTR-HQ, 10.0.13.1 from RTR-REMOTE — never the router's own IP.
• Some Branch /24s are reachable and others are not: the summary mask is wrong. Too long a prefix leaves subnets uncovered; too short leaks space beyond the Branch block.
• Traffic to 10.20.3.0/24 loops between RTR-HQ and RTR-BR: RTR-BR is missing the /22 static to Null0. Longest match keeps the in-use /24s forwarding normally, and only the unused /24 is dropped.
• A ping sourced from a router succeeds while the host test fails: router-sourced tests use a different source address. Always test from CLIENT-BR and CLIENT-REMOTE so the return path is validated too.